The Friction and Wear Properties of Ti–Al–Nb Intermetallics by Plasma Surface Alloying

Abstract

Both plasma chromizing and carburization following plasma chromizing (duplex treatment) for TiAl-Nb alloy were performed, respectively, and the microstructure, dynamic ultra-microhardness, and elastic modulus of the alloying layer were determined. Using silicon nitride (Si 3 N 4 ) balls as the counterface materials, dry sliding friction tests on the substrate, the chromized layer, and the duplex-treated layer were completed by ballon-disk tribometer at room temperature. The results indicated that the duplex-treated layer was mainly composed of Cr 23 C 6 , Cr 2 Nb, pure chromium, and carbon phases, while the chromized layer consisted of Al 8 Cr 5 and Cr 2 Nb phases. The ultra-microhardness of the duplex-treated layer was higher than that of the chromized layer, whereas the elastic modulus of the duplex-treated layer was lower than that of the chromized layer. The friction coefficient of the duplextreated layer was about three times lower than that of the chromized layer, while the wear rate was one order of magnitude lower than that of the chromized layer.

Nano-mechanical characterization of plasma surface tungstenized layer by depth-sensing nano-indentation measurement

“…The experiments were performed in a double-glow plasma surface alloying device, as detailed description of which can be found in the literature [24]. The system pressure of vacuum furnace was set below 10 −4 Pa and then the furnace was supplied with high purity argon gas until the system pressure reached 50 Pa.…”

Microstructure and Wear Resistance of Laser Cladding Nano-Al₂O₃/MCrAlY Composite Graded Coating on TiAl Alloy

“…The problem of poor wear resistance of TiAl alloy has become an urgent problem. In order to improve the wear resistance of TiAl alloy, many surface treatments have been proposed, such as laser cladding composite coatings [2], laser surface alloying [3], plasma surface alloying [4], micro-arc oxidation (MAO) ceramic coating [5], and so on.…”

Mechanical and tribological properties of Cr–Nb double-glow plasma coatings deposited on Ti–Al alloy

“…In recent years, Coatings of Cr and Nb were used to improve the tribological properties of Ti–Al and that has obtained good achievement. Cr can replace Ti and Al position to reform Ti–Al–Cr compound to improve the hardness of the alloy, after a certain amount of Cr is added to Ti–Al alloy [11, 12]. Nb has great capacity of alloying and can maintain good microstructure stability, and it can also form solid solution strengthening phase with Ti and Al to improve the stability of the alloy structure and high temperature strength [13].…”